Preparation of polymeric nanocapsules by radiation induced miniemulsion polymerization

In this research, polystyrene (PSt) nanocapsules with liquid cores were prepared by ⁶⁰Co γ-ray radiation induced miniemulsion polymerization, in which N-vinyl pyrrolidone (NVP) was used as the polar monomer. The characterization of polymer was carried out by ¹H NMR. It was verified that during polymerization, graft copolymerization between poly (pyrrolidone) (PVP) and PSt had taken place instead of random copolymerization. The interfacial tension between polymer and water was reduced because of the grafting reaction that had occurred, which was helpful to form nanocapsules. The influence of the ratio of St to NVP, the type and amount of the surfactant and the monomer/dodocane ratio on the particle morphology was studied by TEM. Finally, the releasing process of the synthesized nanoparticles was monitored by UV-vis measurement.